Collimator for providing constant collimation effect

Abstract

A collimator taking the form of a prolate spheroid (40) comprising radiation attenuating material and featuring a twisted slit comprising radiation transmissive material. The twisted slit featuring first (43) and second (44) apertures arranged such that for each entrance point in one of the apertures there is a direct pathway through the major axis ‘B’ of the prolate spheroid (40), at a pre-determined angle, to a point in the other aperture, such that a compound aperture is formed. For each compound aperture the length of the direct pathway through the prolate spheroid (40) is constant. Rotation of the collimator about the major axis ‘B’, relative to a stationary point at the first aperture (43), steers in angle the compound aperture through the collimator from said stationary point. Such an arrangement allows radiation from a source positioned at said point to be collimated into a beam, the resultant beam being scanned in angle, and the resultant collimation effect being constant across the angular range of the scan.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The invention relates to the field of collimation, and more specifically to a collimator for providing constant collimation effect over a plurality of beam angles, combined with simplicity of design.BACKGROUND TO THE INVENTION[0002]Collimators are used in many applications in order to define the shape and alignment of radiation (which may be electromagnetic waves or beams of particles). For example it is possible to create two-dimensional fan-shaped beams of radiation or one-dimensional pencil beams of radiation using collimators. In particular applications of collimation, such as those using electromagnetic radiation in the visible or near visible spectrum, mirrors and lenses can be used to produce collimated beams. However for electromagnetic radiation with significantly shorter wavelengths and therefore higher energy (such as X-rays and Gamma-rays) or for radiation in the form of beams of particles, a collimator that acts as a filter to the r...

AI Technical Summary

Benefits of technology

The invention is about a collimator which is used to control the collimation of radiation from a source. The collimator has a unique design with a twisted slit that allows for constant collimation. It can rotate around its main axis, creating a continuous scanning beam. This design is simpler and faster than previous methods, and can be used in two dimensions. The collimator can be rotated to specific positions and dwell there, controlling which part of the source can pass through. This allows for precise collimation and improved accuracy.

Problems solved by technology

However for electromagnetic radiation with significantly shorter wavelengths and therefore higher energy (such as X-rays and Gamma-rays) or for radiation in the form of beams of particles, a collimator that acts as a filter to the radiation is required, such that only radiation travelling in desired directions is able to pass through the collimator unhindered.

A common problem with collimation techniques is that the flux at the target is greatly reduced as most of the source waves are blocked by the body of the collimator.

This hinders imaging and analysis techniques by reducing performance and image clarity or by increasing the power of the source needed to attain the same image clarity at equal penetration.

Furthermore, inconsistency in collimation effect (for instance with different beam angles) can further complicate imaging and analysis techniques.

However, such a disc is necessarily large and heavy.

This affects the weight and portability of the whole equipment, requires significant power to maintain the correct rate of rotation and requires multiple moving parts, all of which increase the risk of equipment failure through breakage.

This leads to a variation in the collimation effect and a variation in the size and shape of the beam exiting from the collimator, both of which have a negative impact on the quality of the final image.

However, the variance in path lengths remains, affecting the quality of collimation.

Furthermore, in applications where a scanning beam of radiation is required, the solid cuboid twisted slit collimator needs to be rotated back-and-forth, rather than spun continuously, thus limiting achievable scanning speeds.

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